Process and apparatus for extracting and refining metals and alloys.



A. E. GREENE.

PROCESS AND APPARATUS FOR EXTRAGTING AND REFINING METALS AND ALLOYS.

APPLICATION FILED OUT. 25, 1909.

1,031,257. Patented 2, 1912.

4 SHE HEBT 1.

A I 5 Mi I Ilh A. E. GREENE.

PROCESS AND APPARATUS FOR EXTRAOTING AND REFINING METALS AND ALLOYS.

APPLICATION FILED OUT. 25, 1909.

Patented July 2, 1912.

4. SHEETS-SHEET 2.

A. E. GREENE. PROCESS AND APPARATUS FOR BXTRAGTING AND REFINING METALS AND ALLOYS.

APPLICATION FILED OUT. 25, 1909.

Patented July 2, 1912.

4 SHEETS-SHEET 3.

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, llllllllillllllll A. E. GREENE. PROCESS AND APPARATUS FOR EXTRAGTING AND REFINING METALS AND ALLOYS.

APPLICATION FILED OCT. 25, 1909.

Patented July 2, 1912.

4 SHHETB-SHEET 4.

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UNITED STATES PATENT OFFICE.

ALBERT E. GREENE, OF CHICAGO, ILLINOIS.

PROCESS AND APPARATUS FOR EXTRACTING AND REFINING METALS AND ALLOYS.

Specification of Letters Patent.

Patented July 2, 1912.

Application filed October 25, 1909. Serial No. 524,298.

To all whom it may concern:

Be it known that I, ALBERT E. GREENE, citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Processes and Apparatus for Extracting and Refining Metals and Alloys, of which the following is a full,

clear, concise, and exact description.

My invention relates to a process and apparatus for extracting and refining metals and alloys in general, and more particularly such metals as copper and iron.

It is especially applicable to the production of low-carbon steel.

The object of the invention is to provide a furnace of such construction as will permit of the usual treatment of the metal-to whatever extent is desirable and will then permit of such additional combined electrical and gaseous treatment as may be necessary to produce the required product.

As a process one feature of the invent-ion consists in producing a flow of electric current, preferably by induction, in a definite path in a bath of molten metal and in meanwhile blowing the bath with a gaseous mixture in such manner as to cause a continuous circulation of the metal in a path corresponding to the path of flow of the electric current, the composition of the gaseous agent being such as .to assist in the desired refining operations of-the bath.

Another feature of the process consists in partially refining the metal or alloy in the usual manner in a converter and then electrically heating the bath in' said converter, meanwhile blowing the bath with a gas or gaseous mixture, preferably consisting wholly or in part of the exhaust gas from the converter.

The apparatus of my invention consists of a furnace, such as a converter, rovided with means for producing electric eat localized at a particular place or in a particular path in the furnace, and also provided with twyers arranged to direct a current of gas into the bath in such direction as to produce a circulation of the metal from the less heated portions of the bath to the point of application of the electrically produced heat.

In its preferred embodiment, the apparatus comprises a converter, preferably of the Bessemer type, modified to provide, additional to the main chamber, one or more auxiliary heating chambers, the metal in such latter chambers being preferably heated by iliary chamber or chambers are preferably so arranged that when the vessel is tilted the entrance of slag into .said chambers is prevented.

These and other features of my; invention may be more readily understood by reference to the accompanying drawings, in which, I

Figure 1 is a section, on the line 11 of Fig. 2, of a Bessemer converter modified in accordance with my invention; Fig. 2 is a section on the line 22 of Fig. 1; Fig. 3 is a front elevation of the apparatus; Fig. at is a horizontal sectional view of an open-hearth furnace modified in accordance with my invention; Fig. 5 is a side elevation, partly in section, of the furnace shown in Fig. 4:; Fig.

6 is a section on the line 66 of Fig. 5; Fig. I

channels; and Fig. 8 is a section in the line 88 of Fig. 7.

Similar letters of reference refer to similar parts throughout the severa figures of the drawing.

Referring more particularly to Figs. 1, 2 and 3, the furnace as shown consists essentially of a standard bottom blow converter vessel 1, the twyers 2 being arranged in the usual manner to blow a gas into the bath 3 inclosed in the main chamber 4. The converter is modified, however, to permit both of electric heating of the metal refined therein and of utilizin gas as a circulating and treating agent. ommunicating at its opposite ends with the chamber 4 is a channel 5, which forms the secondary of an induction furnace. The primary winding 6 of the induction furnace is arranged in one of the several well known methods about the transformer core 7. The location of this coil forms no part of the present invention. In short the converter 1 has an induction furnace'S attached thereto, in such manner that the channel 5 of the induction furnace coinmunicates with the chamber of the converter. In the drawings two channels 5 are shown which merge into a common channel 9', such arrangement being suitable for a two-phase system. Obviously the arrangement may be modified to provide for other types of multiphase induction furnaces.

Twyers 10 are so arranged as to blow gas into the metal or bath in such direction as to produce a circulation of the metal between the," channels of the induction furnace and the main chamber. Such twyers 10 are preferabl'y located, as shown in Fig. 1, above the mouth .of the channel 9 and are inclined downwardly toward the surface of the bath. The impact of the gas blown through the twyers 10 upon the surface of the bath is such as to entrain the metal and produce a circulation of the molten bath in a general direction such as is indicated by the arrows in Figs. 1 and2. r V I The vessel 1 is mounted in the usual manner upon hollow trunnions 11. When the vessel is tilted, as shown in Fig. 1, the channels ofthe induction furnace are completely filled with metal and the entrance of corrosive slags into said channels prevented. The tilting of the vessel also permits of the adjustment of the distance and inclination of the surface of the bath with respect to the twyers 10.

The mouth 12 of the converter communicates with a pipe 13, which is removably connected to the mouth 12 and which carries off the exhaust gases from the converter for subsequent utilization. The pipe 13 is journaled to swing in a bearing 14 which-is in axial alinement with the trunnion's, in order that said pipe may swing with the converter.

The pipe 13 communicates with a pipe 15' which conducts the exhaust'gas through one of the regenerators 16, and from thence through the other regenerator to the pipe 17. The pipe 15 is provided with two valves, one extending to each of theregenerators 16, one of said valves being open while the other is closed, thus controlling into which of said regenerators the gas will first flow. Suitable suction apparatus, as for example a blower, is inserted between the two regenerators to assist in the passage of the gas from the one to the other. The exit pipes from the regenerator to the pipe 17 are provided with valves, one of which is open and the other closed, the valve in the exit pipe from the regenerator through which the gas first flows being closed, while the valve in the other exit pipe is open. The function and operation of these regenerators are well understood and hence a detailed description thereof is unnecessary.

The exhaust gas fromthe converter will consist largely of carbon monoxid, and each regenerator is preferably provided with a valve controlled pipe 16 for the admission of air to the regenerator if so desired. Exhaust pipes 18 may also be provided to draw oif the surplus gas for other use if so desired.

The pipe 17 leads to one of the trunnions 11, from which trunnions two branches 19, 20 lead to the twyers 10 and 2, respectively. A valve controlled pipe 21 communicates with the pipe 17 and serves to. supply gas from any suitable source to be used in the treatment'ulitil the generators 16 furnish a sufficient supply.

As'before'stated air ma bemixed with the gas, such air being admitted by the pipes 17 If desired the air for the top-blow twyers 10may be admitted'directly into said twyers by a pipe 22, and the gas from the pipe 17 be supplied in the injector principle, 1

the relative proportions of the mixture being controlled by the speed of the blower 23.

As shown in Fig. 3, the pipes19 and 20 are controlled by valves 24 and 25, respectively, in order that either or both sets of bottom and top blow twyers may be utilized in the blow, as may be desired. Furthermore, I preferably provide means whereby an air blow only may be employed in the usual manner, if desired, and for convenience of illustration a separate valve-controlled pipe 26 is shown connected to the other trunnion 11. Thisconstruction may also serve for admitting a mixture of reducing gas and air simultaneously into the bath from below.

Figs. 4, 5, and 6 illustrate the open-hearth type of furnace modified in accordance with my invention, two sets of induction furnaces 8 being shown disposed upon opposite sides of the main chamber 4"". In this arrangement also the chambers 5 communicate with the chambers 4, and twyers 10 are disposed above the mouth of the common channel 9. Any well known system of regenerators 16 may be employed. The supply of gas from the regenerators may be drawn on the injector principle from said regenerators by'the injector nozzle 28 supplying air or other suitable gas under pressure. Gas from any convenient source and having any suitable composition may be supplied to the twyers 9 by the pipe 29.

Figs. 7 and 8 illustrate a well-known type of induction furnace modified in accordance with my invention. 'In such type of furnace it has been found that the metal in the main chamber 4 isnot sufiiciently heated by the heat developed in the channels, and that it is necessary .to resort to other expedients for maintaining all portions of the bath at the requisite uniform elevated temperature. By

my invention, however, a continuous circulation of the metal from the main chamber into the auxiliary heating channels is effected by the gas olown through the twyers 30. The exhaust gas from the furnace is led out through the pipe 31, and may be utilized in the manner hereinafter described. The gas supplied by the pipe 32 to the wind-box 33 may be there mixed with air or other gas, supplied by the nozzle 34, the relative proportions of the gaseous mixture being controlled on the injector principle, as hereinbefore described.

While I have thus described several types of converters modified in accordance with my invention, I do not wish to be understood as limiting the. invention to the specific structure shown, since it is capable of being embodied in other types of furnaces, and, obviously, different arrangements and changes, within the scope of my invention, may be made even with the types shown and described.

While I furthermore do not wish to be understood as limiting the use of the apparatus hereinafter claimed to the practice of any particular process orprocesses and desire to cover all uses to which the apparatus of my invention may be put, I will now describe certain processes for the practice of which the apparatus is particularly adapted.

The material to be refined is first treated in any known manner in the converter with or without the aid of electric heat and with any suitable gaseous agent for the removal of undesirable oxidizable impurities. After such treatment the bath, heated electrically, is blown with a reducing gas, as for example, the exhaust gas from the converter, for the purpose of further refining the metals, as for example with the view of deoxidizing the metal of the bath, eliminating such impurities as phosphorus and sulfur, and

' minimizing the loss of metal which may have become oxidized in the previous treatment. This process is especially applicable to the product-ion of low-carbon steel from high-carbon iron. However in the production of such steel, I preferably remove the slag resulting from the initial treatment, since such slag, in case the metal has been treated according to the Bessemer or other similar processes, contains iron oxids which, as is well known, tend to prevent the removal of sulfur from the metal. After such removal of the slag, a basic fiux is added to the bath and the molten mass, while electrically heated, is blown with a reducing gas, as above described. Under such conditions sulfur and phosphorus are readily removed even at comparatively low temperatures, as for example, phosphorus at about ].600 C. and sulfur at much lower temperatures.

.The apparatus is also particularly adapted to a modification of the hereinbefore described process which consists in first treatin; the metal which is to be refined, as for example, high-carbon iron, in the usual manner with air or other oxidizing gas in the converter, however, discontinuing the treatment before the completion of the usual blow, thereby uickly removing the larger phrt of the oxidizable impurities with comparatively little loss of the metal itself by oxidation. The partially treated metal is then electrically maintained ata temperature at which the afiinity of oxygen for the contained impurity, as for example, the affinity of oxygen for carbon, is greater than the atfinity of oxygen for the metal of the bath. While the metal is thus maintained at the required temperature, it is subjected to the actlon of a gaseous mixture, composed partly of an oxidlzing agent and partly of a reducing agent, suitable for selectively oxidizing the impurity but unsuitable for a like act-ion on the metal or metals of the bath. This latter part of the treatment is that described and claimed in my copending application Serial No. 488,360, filed April 7th, 1909. The reducing gas employed is preferably the exhaust gas from the converter, which gas consists largely of carbon monoxid (CO).

The apparatus of my invention is also well adapted to the treatment of metals and alloys solely by the process described in my hereinbefore mentioned application for Letters Patent. With such apparatus, gas of a suitable composition can readily be obtained by mixing the exhaust gas from the converter with air or other oxidizing gas. Such mixture, in case air is employed, should be in such proportions that the carbon monoxid is in excess of the oxygen. When the gaseous mixture is blown on the surface of the metal the heat of oxidation of CO into CO is radiated into the bath, and

v the tendency of the endothermic agent CO to lower the temperature of the bath is thereby offset. When the gaseous mixture is used as bottom-blow, the oxidizing gas may then act directly on the element it is desired to oxidize, without the intermediate reaction between the oxygen and the carbon monoxid of the mixture to first form carbon dioxid as in the case of the top-blow. For this reason the bottom-blow is sometimes preferable, since the heat of oxidation is directly transmitted to the bath and such oxidation tends to aid the electric current in heating the bat-h.

The terms high-carbon and low-carbon as used herein are relative terms and are not intended to specify any particular percentage of carbon.

What I claim is 1. In a metal refining furnace, the combination with a vessel adapted to contain a bath of molten metal, said vessel being provided with a main chamber and an auxiliary heating chamber communicating with the main chamber, of twyers arranged to blow gas. into said bath of metal in a direction to produce a continuous circulation of the metal from said main chamber through said auxiliary chamber.

2. In an electric furnace, the-combination with a vessel adapted to contain a bath of molten metal, of means for producing a flow of electric current in the metal contained in a particular portion of said vessel, and twyers arranged to blow gas into said bath of metal in a direction to produce a continuous circulation of the metal in the path of said flow of electric current.

3. In an electric furnace, the combination with a vessel adapted to contain a bath of molten metal, said vessel comprising a main chamber and an auxiliary chamber communicating with said main chamber, means for producing induced electric current flow in the metal contained in said auxiliary chamber, and twyers arranged to blow gas into said bath of metal in a direction to produce a continuous circulation of the metal from said main chamber through said auxiliary chamber.

4. In an electric furnace, the combination with a vessel adapted to contain a bath of molten metal, said Vessel comprising a main chamber and a channel-shaped auxiliary chamber communicating at its opposite ends with said main chamber, means for producing an induced electric current flow in the metal contained in said auxiliary chamber, and inclined twyers arranged above one of the mouths of the channel for blowing gas downwardiy upon the surface of the metal.

In an electric furnace, the combination with a main chamber adapted to contain a bath of molten metal, of two channels lead-Q ing from different portions of said chamber and returning thereto through a common channel, means for producing induced electric currents in the metal contained in said channels, and twyers arranged in proximity to the mouth of said common channel.

0. In an electric furnace, the combination with a vessel adapted to contain a bath of molten metal, means for electrically heating the bath at a particular location in said vessel, and twyers arranged toblow gas into said metal at a point at which the electric heat is communicated to the molten bath.

7. In an electric furnace, the combination with a vessel adapted to contan a bath of molten metal, of means for producing a flow of electric current in the metal contained in a particular portion of said vessel, twyers arranged to blow gas into said bath of metal in a direction to produce a continuous circulation of the metal into the path of said flow of electric current, and means for conducting the exhaust gas from said vessel to said twyers.

8. In an electric furnace, the combination with avvessel adapted to conta a bath of molten metal, of means for producing a flow of electric current in the metal contained in a particular portion of said vessel, twyers arranged to blow gas into said bath of metal in a d1 zection to produce a continuous circulation of the metal into the path of said flow of electric current, means for conducting the exhaust gas from said vessel, admixing it with other gas and conducting such gaseous mixture to said twyers.

9. In an electric furnace, the combination with a main chamber, of a plurality of channel-shaped chambers communicating at their opposite ends with said main chamber, means for producing induced electric currents in "the metal in said channels, and twyers arranged to blow gas into said bath of metal in a dii ection to produce a continuous circulation of the metal from the channels into said main chamber.

10. The combination with a converter of the Bessemer type, of an electric induction furnace communicating with the interior of said converter, and twyers arranged to blow gas into the metal in said converter and thereby to produce a circulation of metal from said converter through the chamber of said induction furnace.

11. The combination with a converter of the Bessemer type, of a multiphase electric induction furnace provided with a plurality of adjoining annular chambers communicating with the interior of said converter the adjacent portions of said annular chambers being in the form of an enlarged common chamber, and twyers arranged above the mouth of said common channel for blowing gas downwardly upon the surface of the metal in said converter.

12. In an electric furnace, the combination with a bottom-blow converter adapted to contain a bath of molten metal, of an induction furnace having a channel-shaped chamber communicating at its opposite ends with the interior of said. converter, and twyers arranged to blow gasinto said bath of metal in a direction to produce a continuous circulation of the metal from the channel into the chamber. of said converter.

13. In an electric furnace, the combinationwith a vessel adapted to contain a bath of molten metal, of means for electrically heating said metal, a twyer leading into said vessel, means for conducting exhaust gas from said vessel to said twyer, an injector nozzle opening into said twyer, and means for forcing gas under pressure through said injector nozzle.

14. The process of extracting and refining metals and alloys, which consists in inclos-.

vessel, producing a flow of electric current in a definite path in said vessel, and blowing said bath with a gas in a direction to produce a continuous circulation of the metal in said vessel in a pat-h corresponding to the path of flow of the electric current.

15. The process of extracting and refining metals and alloys, which conslsts in inclosing a bath of molten metal in a suitable vessel, producing a flow of electric current in a definite path in said vessel, and blowing said'bath with a gas suitable for refining said molten metal, said gas being blown into the bath in a direction to produce a continuous circulation of the metal in said vessel in a path corresponding to the path 015 fiow of the electric current.

- I 16. The process of extracting and refining ous circulation of the metal between said main and auxiliary chambers, and meanwhile tilting said vessel so as to prevent the gntrance of the slaginto said auxiliary cham- 17. The process of extracting and refining metals andalloys, which consists in inclosing a molten bath of metal and slag-producing material in a vessel provided with a main chamber and an auxiliary heating chamber communicating therewith, electrically heating the metal contained in said auxiliary chamber, blowing said vbath with a gaseous treating agent suitable for independently heating the bath, such blow being so applied to the bath as to produce a continuous circulation of the metal between said main and auxiliary chambers, and meanwhile tilting said vessel so as to prevent the entrance of slag into said auxiliary cham- 18. The process of extracting and refining metals and alloys, which consists in inclosing a molten bath of metal and slag-producing material in a vessel provided with a main chamber and an auxiliary heating chamber communicating therewith, electrically heating the metal contained in said auxiliary chamber, directing a current of heat-supplying gas on the surface of the bath in said main chamber in a direction to produce a continuous circulation of the metal between said main and auxiliary chambers.

19. The process of extracting and refining metals and alloys, which consists in inclosing a molten bath of metal and slagproducing material in a vesselprovided with, a main chamber and an auxiliary heating chamber communicating therewith, electrically heating the metal contained in said auxiliary chamber, conducting the exhaust gas from said vessel, mixing with an oxidiz ing gas, and blowing the gaseous mixture into the bath in a direction to produce a continuous circulation of the metal between said main and auxiliary chambers.

In witness whereof, I, hereunto subscribe my name this 23rd, day of October, A. D. 1909.

ALBERT E. GREENE.

Witnesses:

GEORGE E. FOLK, GEo. C. DAVISON. 

